1. Field of the Invention
The present invention relates to a zoom lens having a small and compact size, wide viewing angle, and high magnification, and is thereby being suitable for use in various types of cameras.
2. Description of the Related Art
Recently, optical imaging apparatuses such as digital cameras or digital camcorders that use an image sensing device such as a charge coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) are widely used. In addition, since the demand for high functional optical imaging apparatuses having high magnification and wide viewing angle, low manufacturing costs, and small and lightweight structures has increased, the demand has similarly increased for zoom lenses for use in such optical focusing apparatuses which have high performance, low manufacturing cost, and lightweight structures.
In general, a three-group zoom lens has an appropriate zooming function and a relatively small size, and thus it can be easily used in compact and stylish digital cameras.
While three-group zoom lenses of various designs have been suggested, it is difficult to realize aberration correction and small zoom optics simultaneously. For example, if the focal length of the first lens group is set to be short in order to reduce the size of the zoom lens, the thickness of the zoom lens increases in order to correct the aberration, and thus, the overall length of the zoom lens also increases when the zoom lens is in standby status. In addition, when the first lens group has many aspherical surfaces, it becomes expensive to fabricate.